PHOENIX -- The 2013 season came to an end for the D-backs Sunday afternoon, but the real work begins in earnest Monday.

D-backs general manager Kevin Towers and his staff will meet along with manager Kirk Gibson for most of the day. The agenda will deal with asking why the D-backs for the second year in a row did not live up to preseason predictions and how to go about improving the team for 2014.

The D-backs planned on making the postseason this year, but they instead finished with a .500 record for the second year in a row.

"I would say disappointed," Towers said when asked how he felt about this season. "Really just because our expectations are very high. We fully expect to be in postseason each and every year, and the last two years we've been .500. I'm hoping next year we're not here talking again about finishing 81-81."

The D-backs will discuss their 40-man roster during Monday's meeting and try and assess what their needs are and what help might be available at the higher levels of the Minors, as well as what will be available in the free-agent and trade markets this winter.

It appears the 2014 roster will look pretty similar to the one in '13, with some tweaks.

"I don't anticipate any big changes," Towers said. "I don't see wholesale changes. I like this group of players that we have here."

Towers would like to see the D-backs add a power bat during the offseason. Given the current roster construction, that means adding either a third baseman or corner outfielder.

It's also possible that the D-backs could consider third-base prospect Matt Davidson as that additional power bat, but it seems more likely they will pursue one via a trade this winter.

Trying to evaluate the offense is tricky, because the D-backs did not have their projected Opening Day lineup on the field together very often this year, with Adam Eaton, Cody Ross and Aaron Hill among those who missed large parts of the season.

"I think this year is probably more challenging than last year [to evaluate], because we never really got to see our lineup together all year long with all the guys that missed significant time," Towers said.

Another avenue the D-backs will likely look to improve is the bullpen, which blew 29 saves, the most in the Majors.

The job of closer, however, will be filled by someone currently in the organization. That may or may not be veteran J.J. Putz, who lost his closer's job earlier this year after injuring his elbow. Brad Ziegler did a nice job of filling in during the second half, and he will be a candidate along with Putz, Heath Bell and David Hernandez.

Towers even left open the possibility that prospects Jake Barrett and Matt Stites might be closing for the team next year.

One area of the 'pen that figures to change is the left-handed relief crew.

Matt Reynolds pitched well at the beginning of the year, but went down with an elbow injury in June that required Tommy John surgery. Fellow southpaw Tony Sipp, who was acquired from the Indians last offseason, struggled with his command while Joe Thatcher and rookie Eury De La Rosa each had varying levels of success.

"I think we have to take a strong look at our bullpen," Towers said. "We can make our bullpen better next year. I think we still struggle a little bit with left on left. We thought that was an area that we addressed and we still struggled in that department."

One area that likely will not be addressed Monday is the status of the coaching staff. Indications have been that there will be some changes.